449 FXUS65 KPSR 230513 AFDPSR Area Forecast Discussion National Weather Service Phoenix AZ 1013 PM MST Sun Jun 22 2025 .UPDATE...Updated 06z Aviation Discussion... && .KEY MESSAGES... - Below normal temperatures the next several days followed by a return to above normal as early as Thursday with lower desert highs returning around 110 degrees next weekend - Dry conditions will prevail under mostly clear skies with afternoon and evening breeziness (15 to 25 mile per hour gusts) - Slight chances (10 to 20 percent) for afternoon storms in parts of Southern Gila County beginning as early as Tuesday && .DISCUSSION... Water Vapor imagery shows a large trough-ridge pattern that can be seen spanning across the entire CONUS. This has lead to a heating trend in the eastern CONUS and a cooling trend in the western CONUS, a stark dichotomy between the east and west. The troughing feature in the west, currently positioned just north of the Great Basin, is helping drive cooler temperatures today through Wednesday of this week, with high temperatures expected to be around 2-5 degrees below normal for the lower deserts. Today is forecasted to be coolest day, with most of the lower desert locations just shy of the 100 degree mark. This is quite rare for Phoenix as sub-100 degree highs has been observed 7 times between June 20th-30th during the 2000s (Yuma 11 times & El Centro 13 times). Enjoy these sub-seasonal temperatures while they last since they will gradually trend back to near normal throughout the week as the trough progresses eastward. By Thursday, temperatures will be back to slightly above normal with most locations in the lower desert having forecasted highs between 105-109 degrees as 500 mb heights will be around 587-588 dm. 500mb heights will continue to increase after Thursday, with temperatures expected to be back over the 110 degree mark by the weekend, leading to widespread moderate HeatRisk starting as early as Friday. Additionally, as the trough lingers over the western CONUS, afternoon gusts generally between 15-25 mph will be common over the next several days, especially across Imperial County in southeast CA. The Desert Southwest is still fairly dry this week with PWAT anomalies generally ranging between 40-80% of normal, with the bulk of the more seasonable moisture contained in the southeastern portions of the state. This looks like it will lead to some isolated storms developing in parts of southeast AZ beginning around Tuesday, including as far north as the White Mountains and possibly into southeastern Gila County. Looking a little further ahead, long-range models are not indicating any strong signals for anymore negative height anomalies across the West and there is consensus for the monsoon high becoming established across the Desert Southwest around or just after July 4th and looks to steadily strengthen over the month of July. && .AVIATION...Updated at 0505Z. South Central Arizona including KPHX, KIWA, KSDL, KDVT: No major aviation weather issues under clear skies can be expected throughout the TAF period. The overall wind pattern will exhibit the typical diurnal tendencies with a several hour period from the mid-morning through the mid-afternoon hours on Monday of southerly cross-winds. Wind speeds are expected to remain under 12 kts with periodic gusts into the mid to upper teens expected during the afternoon and evening hours. Southeast California/Southwest Arizona including KIPL and KBLH: No major aviation weather issues under clear skies can be expected throughout the TAF period. At KIPL, current west winds will shift out of the southeast during the overnight period and remain out of the southeast through Monday afternoon before shifting back out of the west during the early evening hours. At KBLH, mainly southerly winds will prevail throughout the period. Wind speeds are expected to remain under 12 kts, however, some periodic gusts approaching 20 kts will be possible at KBLH Monday afternoon and approaching 20-25 kts at KIPL early Monday evening. && .FIRE WEATHER... There are no considerable fire weather concerns through the next 7 days, aside from perhaps some isolated dry thunderstorm impacts in parts of southern Gila County (toward the White Mountains) beginning Tuesday. Winds will be lighter than the previous couple of days, but still breezy in the afternoons and evenings with daily peak gusts up to 15-25 mph. Conditions overall will remain dry with daily minimum RH values down to 5-15% and overnight recoveries only to 20-40%. Near to below normal temperatures are expected through the first half of the week, but will warm through the end of the week and lower desert highs will push back to around the 110 degree mark as early as Friday. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Ryan/Benedict AVIATION...Lojero FIRE WEATHER...Ryan/Benedict